This article is practical if you are only interested performance. In most application(s), when you implement audit trails, you would capture the following:

1) Why the data was modified

2) When the data was modified

3) Who modified the data.

If somebody has access to data via Enterprise Manager, he/she will able be to manipulate the data.This action  will not provide any tracebility or audit trail. If you dealing with very sensitive data, then you have to capture any kind of action related to that data based on the business rules regardless of the tools (QA - Query Analyzer, EM - Enterprise Manager or via Application).

Hence, I doubt the method you suggested/proposed is practical.

Thanks.